text: from django.test import TestCase
  
  from wagtail.tests.utils import WagtailTestUtils
  from wagtail.core.models import Page
  
  from tests.app.models import MetaPage
  from wagtail_meta_preview.utils import GoogleSettings
  from wagtail_meta_preview import meta_settings
  
  
  class TestMetaPreviewGoogleAdminView(TestCase, WagtailTestUtils):
      def setUp(self):
          self.root_page = Page.objects.first()
  
          self.google_page = self.root_page.add_child(
              instance=MetaPage(
                  title="Google Page",
                  seo_title="Google Title",
                  search_description="Google Description",
                  og_title="This is the og title",
                  og_description="This is the og description",
              )
          )
  
      def test_google_default_fallback_titles(self):
          self.google_page.og_title = ""
          self.google_page.save()
  
          google_settings = GoogleSettings(self.google_page)
  
          meta_settings.META_PREVIEW_GOOGLE_TITLE_FIELDS = ""
          self.assertEqual(
              google_settings.get_defaults()["default_title"], "",
          )
  
          meta_settings.META_PREVIEW_GOOGLE_TITLE_FIELDS = "title,another_title"
          self.assertEqual(
              google_settings.get_defaults()["default_title"], self.google_page.title,
          )
  
          self.google_page.og_title = "New google title"
          self.google_page.save()
          meta_settings.META_PREVIEW_GOOGLE_TITLE_FIELDS = (
              "non_existant_field,another_title,og_title"
          )
          self.assertEqual(
              google_settings.get_defaults()["default_title"], self.google_page.og_title,
          )
  
      def test_google_default_fallback_descriptions(self):
          self.google_page.og_description = ""
          self.google_page.save()
          google_settings = GoogleSettings(self.google_page)
  
          meta_settings.META_PREVIEW_GOOGLE_DESCRIPTION_FIELDS = ""
          self.assertEqual(
              google_settings.get_defaults()["default_description"], "",
          )
  
          meta_settings.META_PREVIEW_GOOGLE_DESCRIPTION_FIELDS = (
              "og_description,another_description"
          )
          self.assertEqual(
              google_settings.get_defaults()["default_description"],
              self.google_page.og_description,
          )
  
          self.google_page.og_description = "New google description"
          self.google_page.save()
  
          meta_settings.META_PREVIEW_GOOGLE_DESCRIPTION_FIELDS = (
              "non_existant_field,another_description,og_description"
          )
          self.assertEqual(
              google_settings.get_defaults()["default_description"],
              self.google_page.og_description,
          )
  
      def test_google_default_without_instance(self):
          google_settings = GoogleSettings()
  
          meta_settings.META_PREVIEW_GOOGLE_TITLE_FIELDS = "seo_title,title"
          meta_settings.META_PREVIEW_GOOGLE_DESCRIPTION_FIELDS = "search_description"
  
          self.assertEqual(
              google_settings.get_defaults(),
              {
                  "title_fallback_fields": "seo_title,title",
                  "description_fallback_fields": "search_description",
                  "image_fallback_fields": "",
                  "default_title": "",
                  "default_description": "",
                  "default_image": "",
              },
          )
  